The Cell Biology Core provides major resources to the program project investigators, including normal human cells, an extensive library of characterized melanoma cell lines, patient-derived xenografts, and multiple models to study specific biological processes (Objective 1). The melanoma cell line library encompasses >400 cell lines, at least 200 with known genetic status. To exclude cross-contamination, all experimental cell lines are fingerprinted. Our normal cell panel includes: melanocytes, keratinocytes, fibroblasts, endothelial cells, and skin-derived stem cells. Other resources include adenoviral and lentiviral vectors for growth factors, adhesion molecules, and oncogenes and monoclonal antibodies to melanoma associated biomarkers Three-dimensional cultures of normal human skin (skin equivalents or organotypic cultures of skin) with a dermis of fibroblasts embedded in collagen and an epidermis of melanocytes/melanoma cells and keratinocytes, are also continuously available to the program investigators. This three-dimensional model is superior to standard cell culture techniques because it mimics the in vivo microenvironment for the melanocytes/melanoma cells. For screening studies the Core is providing a robotics-assisted spheroid culture model that allows investigations on melanoma cells displaying in vivo relevant architecture, cell-to cell contacts and invasion, in the presence of a collagen support matrix. The Core additionally provides subcutaneous melanoma growth models for standard experiments, including patient-derived xenografts that are exclusively maintained in vivo and using tissues provided by the Pathology Core B. For Objective 2, the Core will test compounds developed and selected for further analysis and has the knowledge and infrastructure for performing high-throughput screening both in two- and three-dimensional cultures. The responsibility of the Core is to test compounds in an expanded number of cell lines and in quality control testing through different biological assays. For Objective 3, the Core is available to train investigators of the Program in all biological assays and models. Overall, this Core will provide efficient and high quality service to all laboratories within this Program Project.